Fosi Audio LC30 Speaker/Amp Switcher & Meter

[beagleman]

Wow, everyone bashing the meters??

I think "We all know" there is virtually no way to make an actual accurate "Power" meter, as speakers are not resistive loads.
But meters like this, beyond being "Fun", are a nice way to have a relative "idea" of how loud or how much volume of music....to criticize it seems a bit silly.

 

[Sputnik]

In the Amazon reviews and some YT reviews the major complaint is about the sensitivity: that you see no movement at quiet listening volumes, and even at reasonably loud volume, it barely moves (on the most sensitive setting).

Amir writes that sensitivity is good, but I guess he only tested it with dummy loads and on the analyzer, not while playing quiet music.

It's a shame if its only function is fun visuals, that you don't get those unless you crank it.

Comparison with the Douk:

 

[anphex]

Is there/will there be a high power edition up to 500 Watt? I know that's an insane high value, but I would like to not bottleneck my system.

 

[peng]

Too bad we aren’t seeing a modern McIntosh MPM4000 which does have calibrated meters…

http://akdatabase.org/AKview/albums/userpics/10004/MPM4000%20Owners.PDF

(It’s from the automotive group)

Even if calibrated for better accuracy, I think it is sort of anecdotal because it isn't all that useful to see "Watts". It would be useful to see just voltage and current. "Watts" is somewhat useful if measured on the power input side though.

 

[DanielT]

Well, no. Don't waste $150. Instead better spend around $300 and get a TC electronic Clarity M that has excellent value and shows exactly what's going on. And the bling bling factor is there too.

Apples and pears. Having said that, TC electronic Clarity M seems to be good if you are in need of:

The CLARITY M provides a comprehensive set of precision tools essential to the success of any audio producer. Ideally suited to stereo and 5.1 mixing, mastering and post-production,...

TC Electronic | Product | CLARITY M

www.tcelectronic.com

 

[Mojo Warrior]

What are the dimensions ?

Does this match the other amplifiers available from Fosi or legacy components ?

Does Fosi have plans to release an amplifier with VU meters ?

 

[leebergtally]

Too bad about the degradation. I was hoping for a switching device between my two amplifiers and a single set of speakers.. I saw your positive review of the NEOHIPO ET30 VU Meter Speaker Switcher and thought the FOSI unit was the same thing, but obviously it's not.

 

[kyuu]

Too bad about the degradation. I was hoping for a switching device between my two amplifiers and a single set of speakers.

My read of the review is that it will degrade the highest performance amps from super ultra low distortion to merely ultra low distortion. For the vast majority of amps, it probably won't degrade performance at all.

I saw your positive review of the NEOHIPO ET30 VU Meter Speaker Switcher and thought the FOSI unit was the same thing, but obviously it's not.

For the NEOHIPO I believe Amir only tested in parallel. If you notice, when he did the same with the Fosi the tests similarly showed no impact. I wouldn't assume that the NEOHIPO would perform any better when actually using it as a switcher.

 

[AaronJ]

What are the dimensions ?

https://gprivate.com/6dke1

 

[AaronJ]

I am not a fan of the speaker-level meters that so many are producing. Rather see something line-level with VU-meters instead of wattage meters.

 

[kyuu]

My question is: how much audible improvement, if any, would I hear in my system if I used an amp switcher to play music files through a dedicated class D amp in the $600 - $1000 range, like maybe one based on Hypex or Purifi components? I would still use the AV amp for TV.

My hunch is, the decreased distortion might not be that noticeable (maybe in the high treble??), but the increased power well might be. I mostly listen to classical music FWIW, but not exclusively.

Audible improvement? Likely very little to none, in a blind test.

You'd get much more real improvement by getting something that can do proper room correction such as Dirac. Or investing in a measurement microphone and learning how to use REW.

You should probably create your own thread for this, though, rather than discussing it in the review for a totally unrelated product.

 

[Tomino]

Audible improvement? Likely very little to none, in a blind test.

You'd get much more real improvement by getting something that can do proper room correction such as Dirac. Or investing in a measurement microphone and learning how to use REW.

You should probably create your own thread for this, though, rather than discussing it in the review for a totally unrelated product.

Thanks. Have already used REW with a measurement mic. Agree that would come first.

The connection is, I think a lot of folks unhappy with their AV receiver might not realize how easy connecting a second amp might be. The above product opens the option.

 

[Robbo99999]

Seems a bit strange to have such a device with meters that are labelled with numbers/quantities but yet we hear the numbers/meters are nonsense - seems a bit counterintuitive given the inclination of this site. It's not a product that is aimed at me anyway as it's not compatible with any of my systems, but fact that the meters are "nonsensical" doesn't seem aligned with this site. I certainly don't have a bee in my bonnet about it, and I can understand some people just wanting the switching functionality and the overall aesthetic of it, but it'll be interesting to see how it does in the poll.

 

[Ralph_Cramden]

Looks nice, but for those of us who use powered monitors, please provide digital inputs to allow integration into the chain.

 

[GXAlan]

Seems a bit strange to have such a device with meters that are labelled with numbers/quantities but yet we hear the numbers/meters are nonsense - seems a bit counterintuitive given the inclination of this site.

Agreed, especially since Accuphase and McIntosh (and I imagine Audio Research and Classe) will all have proper power meters.

Meters are a fancier way of offering clipping indicators, so beneficial to know how much power you are drawing.

@Fosi Audio , maybe a future revision should just go to “11” instead of nonsensical numbers. Or maybe there’s a real opportunity to have meters that mirror the performance of Accuphase and McIntosh, which would be a great way to have a premium version of your existing amps and products. Look at WiiM and how they offer variations on a theme…

 

[GXAlan]

Wow, everyone bashing the meters??

I think "We all know" there is virtually no way to make an actual accurate "Power" meter, as speakers are not resistive loads.

 

[restorer-john]

Rather see something line-level with VU-meters instead of wattage meters.

Buy a non-working (mechanically) vintage cassette deck, put it in rec/pause and you have some really accurate line level meters. Many have peak hold, adjustable ballistics etc.

 

[phoenixdogfan]

What could be more perfect than putting on Close to the Edge, having yourself a couple of gummies, and getting lost in the music while sitting in a darkened room illuminated only by those amber lights watching those needles move back and forth? Definitely a golfing panther!

 

[beeface]

Looks nice, but for those of us who use powered monitors, please provide digital inputs to allow integration into the chain.

View attachment 396424

what device is that on top of the RME?

 

[Sjkrabbe]

This is a review and measurements of the Fosi Audio LC30 Speaker and amplifier switcher plus "power" meters. It was sent to me by the company and costs US $150.
View attachment 396215
As you see, this is a gorgeous unit, sporting prettier meters than a lot of what vintage audio gear used to have. I always considered a meter with flat line markings as cooler. Both the case and switchgear have a higher quality feel than what I expected. Hitting the selector buttons causes reassuring relay clicks internally. The on/off switch doubles as 3 steps of back light plus off. The gain control has wide range and seems to work better than some of the others I have tested.

The unit is powered by a USB-C connector:
View attachment 396216
You have a choice of two amplifiers and two speakers.

I spent a few minutes to see if the meters show the correct power wattage and they are hopelessly wrong. I would calibrate my amplifier output to a wattage displayed on the meter but when I changed it, the amount of change on the display was wildly different. Contacted Fosi to see if there is an impedance they calibrated to and the answer was: it is not calibrated to anything. It is just for fun.

And fun it is to watch those beautiful meters move. Sensitivity seems good with decent speed.

Fosi Audio LC-30 Measurements
I spent two days trying to measure the impact of LC30 on amplifier performance. I used the Purifi reference design amp to drive the LC30. As I had predicted and feared, the Purifi performance is so good that even slightest change in the impedance of its speaker connection causes third harmonic distortion (seen below). I bought more connectors and built new short speaker cables. I tightened and tightened the connections. Swapped wires and ran a bunch of experiments. But at the end, the impact could not be avoided:
View attachment 396218

There is a dashed blue line which shows the performance of Purifi amp direct. The red mark is the impact of LC30 if you use it as a switcher by routing the speaker output through it. The so called "VCR" (Voltage Coefficient Resistance) shows up more and more as power increases due to resistance variations based on voltage applied. I tried the Topping B100 with same effect. Then I realized that you don't need to use the unit as a switcher. My speaker connectors have a rear banana jack (i.e. they can pass the signal through) so I connected that to LC30. With speaker cables now remaining on the amplifier, we get the performance in green that is overlaid on dashed blue, indicating no impact.

Notice how the noise level is not impacted at all despite the extra cables even in switched mode (the graph before 10 watts). So the issue is only distortion. I am using locking banana connectors above and still registered an impact. If you use anything else, expect a bigger hit. In one case, the connector was a bit less tight and I registered massive distortion and half as much power! So if you are going to use it as a switcher, with a high performance amp, you really need to go the extra mile to get an extra tight connection all around (connector and wire to connector).

Now, if you don't have such a high performance amplifier, then the issue is much less significant to the point of not mattering. Here is LC30 as a switcher in the output of Fosi's own ZA3 amplifier:
View attachment 396220
As you see there is no performance hit even though I have all the extra cables and connectors. Also, some amplifiers will be less impacted by extra connections and cables.

For kicks, I also ran a crosstalk test with Purifi using LC-30 as a switcher:
View attachment 396221

But note that I did not make an attempt to separate my jumper speaker cables so some of this may be due to that.

Given the passive way you can connect the LC30, i.e., not using it as a switcher, I don't see a reason to run other tests.

Conclusions
The LC30 from Fosi brings us a high quality fun meters with switching ability. If you just want dancing meters, I suggest tapping from the amplifier speaker binging to LC30 and not routing your signal through it. That's the way I would use it. If you are going to use it as an AB switch, you should invest in proper set of short cables. Be careful for any AB quality tests as there can be an audible impact here if utmost attention is not paid to wiring (no fault of this unit but in general).

And oh, don't try to use it as a power meter. It is not for that.

The build quality is excellent and the unit is one of the most beautiful of its kind.

I am going to recommend the Fosi LC30 meter and speaker/amplifier switcher for fun factor.
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Hey Amir, I have this switch as well. Have I misunderstood something in your measurement or is a mesurement of impact on signal in turned off mode missing? Or anI just misreading the testresults. Thats the mode where mine lc30 is most of the time - turned off, leading my preferred poweramp’s signal to my preferred speakers. This is My first post in this fantastic community that I have followed passively for years from distant Denmark - thanks for all your work